Doctrine of Claim Differentiation
The Doctrine of Claim Differentiation states that, if necessary to provide claims of differing scope, an ambiguous claim should be interpreted broadly if it is narrowed by a dependent claim, or another claim is present having the same scope plus an additional limitation.
Fed. Cir.: Claim terms to be consistently construed (posted 04/14/15)
In In re: 55 Brake LLC, the Federal Circuit held that the term, “plurality of sensors,” includes a vehicle motion sensor because claim 7 specifies, “wherein one of said plurality of sensors is a vehicle motion sensor.” The Federal Circuit reasons that:
a broader [than an embodiment described in the specification] reading of “plurality of sensors” to include a vehicle motion sensor, is reasonable in light of the plain language of the claims, the specification, and the overall object of the invention to “enable sensors to detect . . . potentially unsafe conditions in or around the vehicle . . . [and] to automatically control the brakes and/or other equipment” as appropriate.
The court further explained its reasoning in a footnote citing Phillips v. AWH Corp.: “In contrast to claims 7 and 9, claim 13 does not explicitly define a vehicle motion sensor as one of the plurality of sensors. But because claim terms are to be construed consistently throughout a patent, our reasoning above applies equally to claim 13.”
Claims narrowed; doctrine of claim differentiation overcome (04/08/07)
In Andersen Corp. v. Fiber Composites, the Fed. Cir. upheld the lower court's construction of four of the six patents at issue (the “Group I” patents) but disagreed on the other two (the Group II patents). The Fed. Cir. limited, “composite composition” to “compositions in pellet or linear extrudate form” because “[t]he Group I common specification repeatedly states that the steps of linear extrusion or pelletization are . . . essential features of the claimed composite composition.” The Fed. Cir. was not persuaded by Anderson's doctrine of claim differentiation argument because, citing Kraft Foods 1) “the written description and prosecution history overcome any presumption arising from the doctrine of claim differentiation.” In addition, the doctrine of claim differentiation is not needed to distinguish the claim scopes since the claims at question contain other differences. With regard to the Group II patents, the Fed. Cir. reversed broad claim construction of the district court because “the specification . . . uses language of requirement, not preference.”
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